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<center><A HREF="lex.htm">Introduction</A> | <A HREF="lex_bib.htm">Bibliography</A></center></center>
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<font size=-1><b>
<A HREF="lex_1.htm">1-9</A> |
<A HREF="lex_a.htm">A</A> |
<A HREF="lex_b.htm">B</A> |
<A HREF="lex_c.htm">C</A> |
<A HREF="lex_d.htm">D</A> |
<A HREF="lex_e.htm">E</A> |
<A HREF="lex_f.htm">F</A> |
<A HREF="lex_g.htm">G</A> |
<A HREF="lex_h.htm">H</A> |
<A HREF="lex_i.htm">I</A> |
<A HREF="lex_j.htm">J</A> |
<A HREF="lex_k.htm">K</A> |
<A HREF="lex_l.htm">L</A> |
<A HREF="lex_m.htm">M</A> |
<A HREF="lex_n.htm">N</A> |
<A HREF="lex_o.htm">O</A> |
<A HREF="lex_p.htm">P</A> |
<A HREF="lex_q.htm">Q</A> |
<A HREF="lex_r.htm">R</A> |
<A HREF="lex_s.htm">S</A> |
<A HREF="lex_t.htm">T</A> |
<A HREF="lex_u.htm">U</A> |
<A HREF="lex_v.htm">V</A> |
<A HREF="lex_w.htm">W</A> |
<A HREF="lex_x.htm">X</A> |
<A HREF="lex_y.htm">Y</A> |
<A href="lex_z.htm">Z</A></b></font>

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<hr>
<p><a name=c>:</a><b>c</b> = <a href="lex_s.htm#speedoflight">speed of light</a>
<p><a name=ca>:</a><b>CA</b> = <a href="#cellularautomaton">cellular automaton</a>
<p><a name=cabertosser>:</a><b>caber tosser</b> Any pattern whose <a href="lex_p.htm#population">population</a> is asymptotic to <i>c</i>.log(<i>t</i>)
for some constant <i>c</i>, and which contains a <a href="lex_g.htm#glider">glider</a> (or other
<a href="lex_s.htm#spaceship">spaceship</a>) bouncing between a slower receding spaceship and a
fixed <a href="lex_r.htm#reflector">reflector</a> which emits a spaceship (in addition to the
reflected one) whenever the bouncing spaceship hits it.
<p>As the receding spaceship gets further away the bouncing spaceship
takes longer to complete each cycle, and so the extra spaceships
emitted by the reflector are produced at increasingly large
intervals. More precisely, if <i>v</i> is the speed of the bouncing
spaceship and <i>u</i> the speed of the receding spaceship, then each
interval is (<i>v</i>+<i>u</i>)/(<i>v</i>-<i>u</i>) times as long as the previous one. The
population at time <i>t</i> is therefore <i>n</i>.log(<i>t</i>)/log((<i>v</i>+<i>u</i>)/(<i>v</i>-<i>u</i>)) + O(1),
where <i>n</i> is the population of one of the extra spaceships (assumed
constant).
<p>The first caber tosser was built by Dean Hickerson in May 1991.
<p><a name=cambridgepulsarcp485672>:</a><b>Cambridge pulsar CP 48-56-72</b> = <a href="lex_p.htm#pulsar">pulsar</a> (The numbers refer to
the populations of the three <a href="lex_p.htm#phase">phases</a>. The Life pulsar was indeed
discovered at Cambridge, like the first real pulsar a few years
earlier.)
<p><a name=canadagoose>:</a><b>Canada goose</b> (<i>c</i>/4 diagonally, p4) Found by Jason Summers, January
1999. It consists of a <a href="lex_g.htm#glider">glider</a> plus a <a href="lex_t.htm#tagalong">tagalong</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OOO..........
O.........OO.
.O......OOO.O
...OO..OO....
....O........
........O....
....OO...O...
...O.O.OO....
...O.O..O.OO.
..O....OO....
..OO.........
..OO.........
</a></pre></td></tr></table></center>
At the time of its discovery the Canada goose was the smallest known
diagonal <a href="lex_s.htm#spaceship">spaceship</a> other than the glider, but this record has since
been beaten, first by the second spaceship shown under <a href="lex_o.htm#orion">Orion</a>, and
more recently by <a href="lex_q.htm#quarter">quarter</a>.
<p><a name=candelabra>:</a><b>candelabra</b> (p3) By Charles Trawick. See also the note under <a href="#cap">cap</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....OO....OO....
.O..O......O..O.
O.O.O......O.O.O
.O..O.OOOO.O..O.
....O.O..O.O....
.....O....O.....
</a></pre></td></tr></table></center>
<p><a name=candlefrobra>:</a><b>candlefrobra</b> (p3) Found by Robert Wainwright in November 1984.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.....O....
.O.OO.O.OO
O.O...O.OO
.O....O...
.....OO...
</a></pre></td></tr></table></center>
The following diagram shows that a pair of these can act in some ways
like <a href="lex_k.htm#killertoads">killer toads</a>. See also <a href="lex_s.htm#snacker">snacker</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....O...........O....
OO.O.OO.O...O.OO.O.OO
OO.O...O.O.O.O...O.OO
...O....O...O....O...
...OO...........OO...
.....................
.....................
.........OOO.........
.........O..O........
.........O...........
.........O...O.......
.........O...O.......
.........O...........
..........O.O........
</a></pre></td></tr></table></center>
<p><a name=canoe>:</a><b>canoe</b> (p1)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
...OO
....O
...O.
O.O..
OO...
</a></pre></td></tr></table></center>
<p><a name=cap>:</a><b>cap</b> The following <a href="lex_i.htm#inductioncoil">induction coil</a>. It can also be easily be
stabilized to form a p3 oscillator - see <a href="#candelabra">candelabra</a> for a slight
variation on this.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.OO.
O..O
OOOO
</a></pre></td></tr></table></center>
<p><a name=carnivalshuttle>:</a><b>carnival shuttle</b> (p12) Found by Robert Wainwright in September 1984
(using <a href="lex_m.htm#mwemulator">MW emulators</a> at the end, instead of the <a href="lex_m.htm#monogram">monograms</a> shown
here).
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.................................O...O
OO...OO..........................OOOOO
.O.O.O...O..O......OO...O..O.......O..
.OO.OO..OO...OO....OO..OO...OO....O.O.
.O.O.O...O..O......OO...O..O.......O..
OO...OO..........................OOOOO
.................................O...O
</a></pre></td></tr></table></center>
<p><a name=carrier>:</a><b>carrier</b> = <a href="lex_a.htm#aircraftcarrier">aircraft carrier</a>
<p><a name=casing>:</a><b>casing</b> That part of the <a href="lex_s.htm#stator">stator</a> of an <a href="lex_o.htm#oscillator">oscillator</a> which is not
adjacent to the <a href="lex_r.htm#rotor">rotor</a>. Compare <a href="lex_b.htm#bushing">bushing</a>.
<p><a name=catacryst>:</a><b>catacryst</b> A 58-cell quadratic growth pattern found by Nick Gotts
in April 2000. This was formerly the smallest known pattern with
superlinear growth, but has since been superseded by the related
<a href="lex_m.htm#metacatacryst">metacatacryst</a>. The catacryst consists of three <a href="lex_a.htm#ark">arks</a> plus a
glider-producing <a href="lex_s.htm#switchengine">switch engine</a>. It produces a block-laying switch
engine every 47616 generations. Each block-laying switch engine has
only a finite life, but the length of this life increases linearly
with each new switch engine, so that the pattern overall grows
quadratically, as an unusual type of MMS <a href="lex_b.htm#breeder">breeder</a>.
<p><a name=catalyst>:</a><b>catalyst</b> An object that participates in a reaction but emerges from
it unharmed. The term is mostly applied to <a href="lex_s.htm#stilllife">still lifes</a>, but can
also be used of <a href="lex_o.htm#oscillator">oscillators</a>, <a href="lex_s.htm#spaceship">spaceships</a>, etc. The still lifes
and oscillators which form a <a href="#conduit">conduit</a> are examples of catalysts.
<p><a name=caterer>:</a><b>caterer</b> (p3) Found by Dean Hickerson, August 1989. Compare
with <a href="lex_j.htm#jam">jam</a>. In terms of its minimum <a href="lex_p.htm#population">population</a> of 12 this is
the smallest p3 <a href="lex_o.htm#oscillator">oscillator</a>. See also <a href="lex_d.htm#doublecaterer">double caterer</a> and
<a href="lex_t.htm#triplecaterer">triple caterer</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..O.....
O...OOOO
O...O...
O.......
...O....
.OO.....
</a></pre></td></tr></table></center>
More generally, any oscillator which serves up a <a href="lex_b.htm#bit">bit</a> in the
same manner may be referred to as a caterer.
<p><a name=caterpillar>:</a><b>Caterpillar</b> A <a href="lex_s.htm#spaceship">spaceship</a> that works by laying tracks at its
front end. The only example constructed to date is a p270 17<i>c</i>/45
spaceship built by Gabriel Nivasch in December 2004, based on work
by himself, Jason Summers and David Bell. This Caterpillar has
a population of about 12 million in each generation and was put
together by a computer program that Nivasch wrote. It is by far
the largest and most complex Life object ever constructed.
<p>The 17<i>c</i>/45 Caterpillar is based on the following reaction between
a <a href="lex_p.htm#piheptomino">pi-heptomino</a> and a <a href="lex_b.htm#blinker">blinker</a>:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
...............O
O.............OO
O............OO.
O.............OO
...............O
</a></pre></td></tr></table></center>
In this reaction, the pi moves forward 17 cells in the course of 45
generations, while the blinker moves back 6 cells and is rephased.
This reaction has been known for many years, but it was only in
September 2002 that David Bell suggested that it could be used to
build a 17<i>c</i>/45 spaceship, based on a reaction he had found in which
pis crawling along two rows of blinkers interact to emit a glider
every 45 generations. Similar glider-emitting interactions were
later found by Gabriel Nivasch and Jason Summers. The basic idea of
the spaceship design is that streams of gliders created in this way
can be used to construct fleets of <a href="lex_s.htm#standardspaceship">standard spaceships</a> which convey
gliders to the front of the blinker tracks, where they can be used to
build more blinkers.
<p>A different Caterpillar may be possible based on the following
reaction, in which the pattern at top left reappears after 31
generations displaced by (13,1), having produced a new NW-travelling
glider. In this case the tracks would be waves of backward-moving
gliders.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.OO.....................
...O....................
...O.OO.................
OOO....O................
.......O................
.....OOO................
........................
........................
........................
........................
........................
........................
.....................OOO
.....................O..
......................O.
</a></pre></td></tr></table></center>
<p><a name=catherinewheel>:</a><b>Catherine wheel</b> = <a href="lex_p.htm#pinwheel">pinwheel</a>
<p><a name=cauldron>:</a><b>cauldron</b> (p8) Found in 1971 independently by Don Woods and Robert
Wainwright. Compare with <a href="lex_h.htm#hertzoscillator">Hertz oscillator</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.....O.....
....O.O....
.....O.....
...........
...OOOOO...
O.O.....O.O
OO.O...O.OO
...O...O...
...O...O...
....OOO....
...........
....OO.O...
....O.OO...
</a></pre></td></tr></table></center>
<p><a name=cavity>:</a><b>cavity</b> = <a href="lex_e.htm#eaterplug">eater plug</a>
<p><a name=cell>:</a><b>cell</b> The fundamental unit of space in the Life universe. The term is
often used to mean a live cell - the sense is usually clear from the
context.
<p><a name=cellularautomaton>:</a><b>cellular automaton</b> A certain class of mathematical objects of which
<a href="lex_l.htm#life">Life</a> is an example. A cellular automaton consists of a number of
things. First there is a positive integer <i>n</i> which is the dimension
of the cellular automaton. Then there is a finite set of states <i>S</i>,
with at least two members. A state for the whole cellular automaton
is obtained by assigning an element of <i>S</i> to each point of the
<i>n</i>-dimensional lattice <span class="b">Z</span><sup><i>n</i></sup> (where <span class="b">Z</span> is the set of all integers).
The points of <span class="b">Z</span><sup><i>n</i></sup> are usually called cells. The cellular automaton
also has the concept of a neighbourhood. The neighbourhood <i>N</i> of the
origin is some finite (nonempty) subset of <span class="b">Z</span><sup><i>n</i></sup>. The neighbourhood
of any other cell is obtained in the obvious way by translating that
of the origin. Finally there is a transition rule, which is a
function from <i>S</i><sup><i>N</i></sup> to <i>S</i> (that is to say, for each possible state of
the neighbourhood the transition rule specifies some cell state).
The state of the cellular automaton evolves in discrete time, with
the state of each cell at time <i>t</i>+1 being determined by the state
of its neighbourhood at time <i>t</i>, in accordance with the transition
rule.
<p>There are some variations on the above definition. It is common
to require that there be a quiescent state, that is, a state such
that if the whole universe is in that state at generation 0 then it
will remain so in generation 1. (In Life the OFF state is quiescent,
but the ON state is not.) Other variations allow spaces other than
<span class="b">Z</span><sup><i>n</i></sup>, neighbourhoods that vary over space and/or time, probabilistic
or other non-deterministic transition rules, etc.
<p>It is common for the neighbourhood of a cell to be the 3x...x3
(hyper)cube centred on that cell. (This includes those cases where
the neighbourhood might more naturally be thought of as a proper
subset of this cube.) This is known as the Moore neighbourhood.
<p><a name=centinal>:</a><b>centinal</b> (p100) Found by Bill Gosper. This combines the mechanisms
of the p46 and p54 shuttles (see <a href="lex_t.htm#twinbeesshuttle">twin bees shuttle</a> and
<a href="lex_p.htm#p54shuttle">p54 shuttle</a>).
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OO................................................OO
.O................................................O.
.O.O.....................OO.....................O.O.
..OO........O............OO............OO.......OO..
...........OO..........................O.O..........
..........OO.............................O..........
...........OO..OO......................OOO..........
....................................................
....................................................
....................................................
...........OO..OO......................OOO..........
..........OO.............................O..........
...........OO..........................O.O..........
..OO........O............OO............OO.......OO..
.O.O.....................OO.....................O.O.
.O................................................O.
OO................................................OO
</a></pre></td></tr></table></center>
<p><a name=century>:</a><b>century</b> (stabilizes at time 103) This is a common pattern which
evolves into three <a href="lex_b.htm#block">blocks</a> and a <a href="lex_b.htm#blinker">blinker</a>. In June 1996 Dave
Buckingham built a neat p246 glider <a href="lex_g.htm#gun">gun</a> using a century as the
engine. See also <a href="lex_b.htm#bookend">bookend</a> and <a href="lex_d.htm#diuresis">diuresis</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..OO
OOO.
.O..
</a></pre></td></tr></table></center>
<p><a name=chemist>:</a><b>chemist</b> (p5)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.......O.......
.......OOO.....
..........O....
.....OOO..O..OO
....O.O.O.O.O.O
....O...O.O.O..
.OO.O.....O.OO.
..O.O.O...O....
O.O.O.O.O.O....
OO..O..OOO.....
....O..........
.....OOO.......
.......O.......
</a></pre></td></tr></table></center>
<p><a name=cheptomino>:</a><b>C-heptomino</b> Name given by Conway to the following <a href="lex_h.htm#heptomino">heptomino</a>, a less
common variant of the <a href="lex_b.htm#bheptomino">B-heptomino</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.OOO
OOO.
.O..
</a></pre></td></tr></table></center>
<p><a name=cheshirecat>:</a><b>Cheshire cat</b> A block <a href="lex_p.htm#predecessor">predecessor</a> by C. R. Tompkins that
unaccountably appeared both in Scientific American and in
<a href="lex_w.htm#winningways">Winning Ways</a>. See also <a href="lex_g.htm#grin">grin</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.O..O.
.OOOO.
O....O
O.OO.O
O....O
.OOOO.
</a></pre></td></tr></table></center>
<p><a name=chickenwire>:</a><b>chicken wire</b> A type of <a href="lex_s.htm#stable">stable</a> <a href="lex_a.htm#agar">agar</a> of <a href="lex_d.htm#density">density</a> 1/2. The
simplest version is formed from the tile:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OO..
..OO
</a></pre></td></tr></table></center>
But the "wires" can have length greater than two and need not
all be the same. For example:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OO...OOOO.....
..OOO....OOOOO
</a></pre></td></tr></table></center>
<p><a name=cigar>:</a><b>cigar</b> = <a href="lex_m.htm#mango">mango</a>
<p><a name=cisbeacononanvil>:</a><b>cis-beacon on anvil</b> (p2)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
...OO.
....O.
.O....
.OO...
......
.OOOO.
O....O
.OOO.O
...O.OO
</a></pre></td></tr></table></center>
<p><a name=cisbeaconontable>:</a><b>cis-beacon on table</b> (p2)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..OO
...O
O...
OO..
....
OOOO
O..O
</a></pre></td></tr></table></center>
<p><a name=cisboatwithtail>:</a><b>cis-boat with tail</b> (p1)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.O...
O.O..
OO.O.
...O.
...OO
</a></pre></td></tr></table></center>
<p><a name=cisfusewithtwotails>:</a><b>cis fuse with two tails</b> (p1) See also <a href="lex_p.htm#pulsarquadrant">pulsar quadrant</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
...O..
.OOO..
O...OO
.O..O.
..O.O.
...O..
</a></pre></td></tr></table></center>
<p><a name=cismirroredrbee>:</a><b>cis-mirrored R-bee</b> (p1)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.OO.OO.
O.O.O.O
O.O.O.O
.O...O.
</a></pre></td></tr></table></center>
<p><a name=cissnake>:</a><b>cis snake</b> = <a href="#canoe">canoe</a>
<p><a name=clean>:</a><b>clean</b> Opposite of <a href="lex_d.htm#dirty">dirty</a>. A reaction which produces a small number
of different products which are desired or which are easily deleted
is said to be clean. For example, a <a href="lex_p.htm#puffer">puffer</a> which produces just one
object per period is clean. Clean reactions are useful because they
can be used as building blocks in larger constructions.
<p>When a <a href="lex_f.htm#fuse">fuse</a> is said to be clean, or to burn cleanly, this usually
means that no debris at all is left behind.
<p><a name=clock>:</a><b>clock</b> (p2) Found by Simon Norton, May 1970. This is the fifth or
sixth most common <a href="lex_o.htm#oscillator">oscillator</a>, being about as frequent as the
<a href="lex_p.htm#pentadecathlon">pentadecathlon</a>, but much less frequent than the <a href="lex_b.htm#blinker">blinker</a>, <a href="lex_t.htm#toad">toad</a>,
<a href="lex_b.htm#beacon">beacon</a> or <a href="lex_p.htm#pulsar">pulsar</a>. But it's surprisingly rare considering its
small size.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..O.
O.O.
.O.O
.O..
</a></pre></td></tr></table></center>
<p><a name=clockii>:</a><b>clock II</b> (p4) Compare with <a href="lex_p.htm#pinwheel">pinwheel</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
......OO....
......OO....
............
....OOOO....
OO.O....O...
OO.O..O.O...
...O..O.O.OO
...O.O..O.OO
....OOOO....
............
....OO......
....OO......
</a></pre></td></tr></table></center>
<p><a name=cloudofsmoke>:</a><b>cloud of smoke</b> = <a href="lex_s.htm#smoke">smoke</a>
<p><a name=cloverleaf>:</a><b>cloverleaf</b> This name was given by Robert Wainwright to his p2
oscillator <a href="lex_w.htm#washingmachine">washing machine</a>. But Achim Flammenkamp also gave this
name to <a href="lex_a.htm#achimsp4">Achim's p4</a>.
<p><a name=cluster>:</a><b>cluster</b> Any pattern in which each live cell is connected to every
other live cell by a path that does not pass through two consecutive
dead cells. This sense is due to Nick Gotts, but the term has also
been used in other senses, often imprecise.
<p><a name=cnwh>:</a><b>CNWH</b> Conweh, creator of the Life universe.
<p><a name=coeship>:</a><b>Coe ship</b> (<i>c</i>/2 orthogonally, p16) A <a href="lex_p.htm#pufferengine">puffer engine</a> discovered by Tim
Coe in October 1995.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....OOOOOO
..OO.....O
OO.O.....O
....O...O.
......O...
......OO..
.....OOOO.
.....OO.OO
.......OO.
</a></pre></td></tr></table></center>
<p><a name=coesp8>:</a><b>Coe's p8</b> (p8) Found by Tim Coe in August 1997.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OO..........
OO..OO......
.....OO.....
....O..O....
.......O..OO
.....O.O..OO
</a></pre></td></tr></table></center>
<p><a name=colorizedlife>:</a><b>colorized Life</b> A <a href="#cellularautomaton">cellular automaton</a> which is the same as Life
except for the use of a number of different ON states ("colours").
All ON states behave the same for the purpose of applying the Life
rule, but additional rules are used to specify the colour of the
resulting ON cells. Examples are <a href="lex_i.htm#immigration">Immigration</a> and <a href="lex_q.htm#quadlife">QuadLife</a>.
<p><a name=colourofaglider>:</a><b>colour of a glider</b> The colour of a <a href="lex_g.htm#glider">glider</a> is a property of the
glider which remains constant while the glider is moving along a
straight path, but which can be changed when the glider bounces off
a <a href="lex_r.htm#reflector">reflector</a>. It is an important consideration when building
something using reflectors.
<p>The colour of a glider can be defined as follows. First
choose some cell to be the origin. This cell is then considered
to be white, and all other cells to be black or white in a
checkerboard pattern. (So the cell with coordinates (<i>m</i>,<i>n</i>) is
white if <i>m</i>+<i>n</i> is even, and black otherwise.) Then the colour of
a glider is the colour of its leading cell when it is in a phase
which can be rotated to look like this:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OOO
..O
.O.
</a></pre></td></tr></table></center>
<p>A reflector which does not change the colour of gliders obviously
cannot be used to move a glider onto a path of different colour than
it started on. But a 90-degree reflector which does change the
colour of gliders is similarly limited, as the colour of the
resulting glider will depend only on the direction of the glider,
no matter how many reflectors are used. For maximum flexibility,
therefore, both types of reflector are required.
<p><a name=complementaryblinker>:</a><b>complementary blinker</b> = <a href="lex_f.htm#foreandback">fore and back</a>
<p><a name=compression>:</a><b>compression</b> = <a href="lex_r.htm#repeattime">repeat time</a>
<p><a name=conduit>:</a><b>conduit</b> Any arrangement of <a href="lex_s.htm#stilllife">still lifes</a> and/or <a href="lex_o.htm#oscillator">oscillators</a> which
move an active object to another location, perhaps also transforming
it into a different active object at the same time, but without
leaving any permanent debris (except perhaps gliders, or other
spaceships) and without any of the still lifes or oscillators being
permanently damaged. Probably the most important conduit is the
following remarkable one (Dave Buckingham, July 1996) in which a
<a href="lex_b.htm#bheptomino">B-heptomino</a> is transformed into a <a href="lex_h.htm#herschel">Herschel</a> in 59 generations.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.........OO.O
O.OO......OOO
OO.O.......O.
.............
.........OO..
.........OO..
</a></pre></td></tr></table></center>
<p><a name=confusedeaters>:</a><b>confused eaters</b> (p4) Found by Dave Buckingham before 1973.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
O..........
OOO........
...O.......
..O........
..O..O.....
.....O.....
...O.O.....
...OO..OO..
.......O.O.
.........O.
.........OO
</a></pre></td></tr></table></center>
<p><a name=converter>:</a><b>converter</b> A <a href="#conduit">conduit</a> in which the input object is not of the same
type as the output object. This term tends to be preferred when
either the input object or the output object is a <a href="lex_s.htm#spaceship">spaceship</a>.
<p>The following diagram shows a p8 <a href="lex_p.htm#piheptomino">pi-heptomino</a>-to-<a href="lex_h.htm#hwss">HWSS</a>
converter. This was originally found by Dave Buckingham in a
larger form (using a <a href="lex_f.htm#figure8">figure-8</a> instead of the <a href="lex_b.htm#boat">boat</a>). The
improvement shown here is by Bill Gosper (August 1996). Dieter
Leithner has since found (much larger) <a href="lex_o.htm#oscillator">oscillators</a> of periods 44,
46 and 60 to replace the <a href="lex_k.htm#koksgalaxy">Kok's galaxy</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.O.O..O........
.OOO.O.OO......
O......O.....O.
.O.....OO...O.O
.............OO
OO.....O.......
.O......O......
OO.O.OOO.......
..O..O.O.......
............OOO
............O.O
............O.O
</a></pre></td></tr></table></center>
<p><a name=convoy>:</a><b>convoy</b> A collection of <a href="lex_s.htm#spaceship">spaceships</a> all moving in the same direction
at the same speed.
<p><a name=corder>:</a><b>Corder-</b> Prefix used for things involving <a href="lex_s.htm#switchengine">switch engines</a>, after
Charles Corderman.
<p><a name=corderengine>:</a><b>Corder engine</b> = <a href="lex_s.htm#switchengine">switch engine</a>
<p><a name=cordergun>:</a><b>Cordergun</b> A <a href="lex_g.htm#gun">gun</a> firing <a href="#cordership">Corderships</a>. The first was built by Jason
Summers in July 1999, using a <a href="lex_g.htm#glidersynthesis">glider synthesis</a> by Stephen Silver.
<p><a name=cordership>:</a><b>Cordership</b> Any <a href="lex_s.htm#spaceship">spaceship</a> based on <a href="lex_s.htm#switchengine">switch engines</a>. These
necessarily move at a speed of <i>c</i>/12 diagonally with a period of 96
(or a multiple thereof). The first was found by Dean Hickerson
in April 1991. Corderships are the slowest spaceships so far
constructed, although arbitrarily slow spaceships are known to exist
(see <a href="lex_u.htm#universalconstructor">universal constructor</a>). Hickerson's original Cordership used
13 switch engines. He soon reduced this to 10, and in August 1993
to 7. In July 1998 he reduced it to 6. In January 2004, Paul Tooke
found the 3-engine Cordership shown below.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
................................OO.O...........................
...............................OOO.O......O.O..................
..............................O....O.O....O....................
...............................OO......O.O...O.................
................................O...O..O..OO...................
...................................O.OO...O....................
..................................O.O................OO........
..................................O.O................OO........
...............................................................
...............................................................
...............................................................
...............................................................
...............................................................
...............................................................
.............................................................OO
....................................................OO.......OO
.......................................O.........O.OOOO........
..................................O...OOOOO.....OO.O...OO......
.................................O.O.......OO....O..OO.OO......
.................................O.......O.OO.....OOOOOO.......
..................................O........OO......O...........
...................................O...OOOO....................
........................................OOO....................
........................O.O.........OO.........................
........................O.O.O......O.O.........................
.......................O..OO.O....OO...........................
........................OO...O.O.OO.O..........................
........................OO...OO.OOOOO..........................
............................O.OO...OO..........................
...........................O.O.................................
..OO.O.........................................................
.OOO.O......O.O................................................
O....O.O....O..................................................
.OO......O.O...O...............................................
..O...O..O..OO...........O.....................................
.....O.OO...O...........OOO....................................
....O.O.................O..O...................................
....O.O................O....O..................................
........................O......................................
...............................................................
........................O..O...................................
.........................O.O...................................
...............................................................
.....................O.........................................
....................OOO........................................
...................OO.OO.......................................
.........O........OO.O.....O...................................
....O...OOOOO....OO......OO....................................
...O.O.......OO..OO.......OO...................................
...O.......O.OO................................................
....O........OO................................................
.....O...OOOO..................................................
..........OOO..................................................
...............................................................
...............................................................
...............................................................
...........OO..................................................
...........OO..................................................
</a></pre></td></tr></table></center>
<p><a name=cousins>:</a><b>cousins</b> (p3) This contains two copies of the <a href="lex_s.htm#stillater">stillater</a> <a href="lex_r.htm#rotor">rotor</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.....O.OO....
...OOO.O.O...
O.O......O...
OO.OO.OO.O.OO
...O.O....O.O
...O.O.OOO...
....OO.O.....
</a></pre></td></tr></table></center>
<p><a name=cover>:</a><b>cover</b> The following <a href="lex_i.htm#inductioncoil">induction coil</a>. See <a href="lex_s.htm#scrubber">scrubber</a> for an example
of its use.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....O
..OOO
.O...
.O...
OO...
</a></pre></td></tr></table></center>
<p><a name=coveredtable>:</a><b>covered table</b> = <a href="#cap">cap</a>
<p><a name=cow>:</a><b>cow</b> (<i>c</i> p8 fuse)
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
OO.......OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO.....
OO....O.OOO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO...OO
....OO.O.................................................O.O
....OO...OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO..
....OO.O..................................................O.
OO....O.OOO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO.
OO.......OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO..OO.....
</a></pre></td></tr></table></center>
<p><a name=cppulsar>:</a><b>CP pulsar</b> = <a href="lex_p.htm#pulsar">pulsar</a>
<p><a name=crane>:</a><b>crane</b> (<i>c</i>/4 diagonally, p4) The following <a href="lex_s.htm#spaceship">spaceship</a> found by Nicolay
Beluchenko in September 2005, a minor modification of a <a href="lex_t.htm#tubeater">tubeater</a>
found earlier by Hartmut Holzwart. The wing is of the same form as
in the <a href="lex_s.htm#swan">swan</a> and <a href="#canadagoose">Canada goose</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.OO.................
OO..................
..O.................
....OO...O..........
....OO..O.O.........
.......OO.O.........
.......OO...........
.......OO...........
.................OO.
.........O....OO.O..
.........OOO..OO....
.........OOO..OO....
..........OO........
....................
............O.......
...........OO.......
...........O........
............O.......
....................
.............OO.....
..............O.OO..
..................O.
...............OO...
...............OO...
.................O..
..................OO
</a></pre></td></tr></table></center>
<p><a name=cross>:</a><b>cross</b> (p3) Found by Robert Wainwright in October 1989.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..OOOO..
..O..O..
OOO..OOO
O......O
O......O
OOO..OOO
..O..O..
..OOOO..
</a></pre></td></tr></table></center>
In February 1993, Hartmut Holzwart noticed that this is merely the
smallest of an infinite family of p3 oscillators. The next smallest
member is shown below.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..OOOO.OOOO..
..O..O.O..O..
OOO..OOO..OOO
O...........O
O...........O
OOO.......OOO
..O.......O..
OOO.......OOO
O...........O
O...........O
OOO..OOO..OOO
..O..O.O..O..
..OOOO.OOOO..
</a></pre></td></tr></table></center>
<p><a name=crowd>:</a><b>crowd</b> (p3) Found by Dave Buckingham in January 1973.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
...........O..
.........OOO..
.....OO.O.....
.....O...O....
.......OO.O...
...OOOO...O...
O.O.....O.O.OO
OO.O.O.....O.O
...O...OOOO...
...O.OO.......
....O...O.....
.....O.OO.....
..OOO.........
..O...........
</a></pre></td></tr></table></center>
<p><a name=crown>:</a><b>crown</b> The p12 part of the following p12 <a href="lex_o.htm#oscillator">oscillator</a>, where it is
<a href="lex_h.htm#hassle">hassled</a> by <a href="#caterer">caterer</a>, a <a href="lex_j.htm#jam">jam</a> and a <a href="lex_h.htm#hwemulator">HW emulator</a>. This oscillator
was found by Noam Elkies in January 1995.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
..........O...........
..........O......O....
...O....O...O...OO....
...OO....OOO..........
.........OOO..OOO..O.O
.O..OOO.........O.OOOO
O.O.O...............OO
O..O..................
.OO........OO.........
......OO.O....O.OO....
......O..........O....
.......OO......OO.....
....OOO..OOOOOO..OOO..
....O..O........O..O..
.....OO..........OO...
</a></pre></td></tr></table></center>
<p><a name=crucible>:</a><b>crucible</b> = <a href="#cauldron">cauldron</a>
<p><a name=crystal>:</a><b>crystal</b> A regular growth that is sometimes formed when a stream of
<a href="lex_g.htm#glider">gliders</a>, or other <a href="lex_s.htm#spaceship">spaceships</a>, is fired into some junk.
<p>The most common example is initiated by the following collision
of a glider with a <a href="lex_b.htm#block">block</a>. With a glider stream of even <a href="lex_p.htm#period">period</a>
at least 82, this gives a crystal which forms a pair <a href="lex_b.htm#beehive">beehives</a> for
every 11 gliders which hit it.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
.O......
..O...OO
OOO...OO
</a></pre></td></tr></table></center>
<p><a name=cuphook>:</a><b>cuphook</b> (p3) Found by Rich Schroeppel, October 1970. This is one of
only three essentially different p3 <a href="lex_o.htm#oscillator">oscillators</a> with only three
cells in the <a href="lex_r.htm#rotor">rotor</a>. The others are <a href="lex_1.htm#a123">1-2-3</a> and <a href="lex_s.htm#stillater">stillater</a>.
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....OO...
OO.O.O...
OO.O.....
...O.....
...O..O..
....OO.O.
.......O.
.......OO
</a></pre></td></tr></table></center>
The above is the original form, but it can be made more compact:
<center><table cellspacing=0 cellpadding=0><tr><td><pre><a href="lexpatt:">
....OO.
...O.O.
...O...
OO.O...
OO.O..O
...O.OO
...O...
..OO...
</a></pre></td></tr></table></center>
<p><a name=curl>:</a><b>curl</b> = <a href="lex_l.htm#loop">loop</a>
<hr>
<center>
<font size=-1><b>
<a href="lex_1.htm">1-9</a> |
<a href="lex_a.htm">A</a> |
<a href="lex_b.htm">B</a> |
<a href="lex_c.htm">C</a> |
<a href="lex_d.htm">D</a> |
<a href="lex_e.htm">E</a> |
<a href="lex_f.htm">F</a> |
<a href="lex_g.htm">G</a> |
<a href="lex_h.htm">H</a> |
<a href="lex_i.htm">I</a> |
<a href="lex_j.htm">J</a> |
<a href="lex_k.htm">K</a> |
<a href="lex_l.htm">L</a> |
<a href="lex_m.htm">M</a> |
<a href="lex_n.htm">N</a> |
<a href="lex_o.htm">O</a> |
<a href="lex_p.htm">P</a> |
<a href="lex_q.htm">Q</a> |
<a href="lex_r.htm">R</a> |
<a href="lex_s.htm">S</a> |
<a href="lex_t.htm">T</a> |
<a href="lex_u.htm">U</a> |
<a href="lex_v.htm">V</a> |
<a href="lex_w.htm">W</a> |
<a href="lex_x.htm">X</a> |
<a href="lex_y.htm">Y</a> |
<A href="lex_z.htm">Z</A></b></font>

</center>
<hr>
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